System of electrodes for electric glow discharge tubes



Jan. 2, 1934. G $518+ 1,941,956

SYSTEM OF ELECTRODES FOR ELECTRIC GLOW DISCHARGE TUBES Filed March 12,1931 Fig. 1

Patented Jan. 2, 1934 PATENT OFFICE SYSTEM OF ELECTRODES FOR ELECTRICGLOW DISCHARGE TUBES Georg Seibt, Berlin-Schoneberg, Germany ApplicationMarch 12, 1931, Serial No. 522,123, and in Germany May 21, 1930 5Claims. (Cl. 25027.5)

It is known in the art that in the case of glow discharges the cathodedrop can be reduced when the cathode is constructed more or less as ahollow member. In this case several portions of the surface of thecathodes from which discharges take place face one another in some wayor other.

A simple construction consists in this that two plates are arrangedopposite one another at a distance of a few millimetres. In this casethe main discharge current does not proceed from the surfaces which lieoutside but substantially only from the surfaces which are opposite oneanother. The physical reason therefor is to be found in this that spacedischarges which tend to be produced at the cathode by positivelycharged ions, are dispersed by the electrons which proceed from theother surfaces of the hollow cathode.

The object of the present invention is to utilize the action of thehollow cathodes hereinbefore referred to in connection with the systemof electrodes for glow discharge'amplifiers. Such a system consists, asis well known, of two discharge electrodes, viz, a cathode and an an-.ode, the discharge between which serves as a 1 siderably to increasethe action of such glow discharge tubes so as to allow a greater yieldin electrons for the amplifying current to be obtained with thereduction in the cathode drop, whereby the output of the amplifier isincreased.

Various modes of carrying the. invention into effect are illustrated, byway of example, in the accompanying drawing in which Fig. 1 shows a formof cathode, Figure 2 is a modified construction thereof and Figure 3 isa cross-section of a complete system of electrodes for a glow dischargeamplifying valve.

Figure 1 shows a hollow cathode, which consists of a sheet metalcylinder 2 provided with a longitudinal slot 1 through which thedischarges can pass to the desired electrodes. The width of thelongitudinal slot 1 may vary; it may be very small or so wide that itamounts, for instance, to half the peripheral surface of the cylinder.In order to impart a greater stability to the cathode, the same may beprovided at its two ends with closing pieces 11 and d2, which may bemade of metal or of insulating material. It is also preferable not tocontinue the longitudinal slot 1 right up to the edges at the ends ofthe cylinder but to stop short of these, as is illustrated in Figure 2.This also allows the mechanical stability of the cathode to beincreased.

Figure 3 illustrates, by way of example, the manner in which the hollowcathode may be combined with a glow discharge amplifying tube. It willbe seen that in this arrangement, which is illustrated in cross-section,the amplifying anode az lies in the axis of a concentric system. Theamplifying anode is shown as being surrounded by a cylindrical coilconstituting the controlling electrode .9. In its turn the latter isconcentrically surrounded by the discharge anode or, preferablyconsisting of a cylinder from which longitudinal strips have been cutout so as to form openings through which the electrons coming from theglow discharge field can be drawn into the actual amplifying space. Incontradistinction to the arrangements hitherto proposed, the cathode isnot constituted by a plurality of individual strips or wires arrangedbehind the solid parts of the discharge anode but by individual smallcylinders k: which have a diameter of a few millimetres, for instance 3mms. Their length is equal to the length of the other electrodes, thatis to say several centimetres. In order to retain the screening effectof the discharge anode described in my prior applications concerningglow discharge amplifying tubes, the 90 individual parts 1c of thehollow cathode are preferably so dimensioned and arranged that they arecompletely screened. However, presumably it would not be dangerous if astraight line path proceeded from the outer walls of the individualcathode parts to the amplifying electrodes, since owing to the action ofthe hollow cathode is hereinbefore described, only that part of thedischarge is mainly effective as regards the average yield in electrons,which pass-through the slotlike openings 1.

If required, the outer walls of the cathode cylinder may be surroundedby insulating material, which prevents any discharge taking place fromthese parts.

It is to be understood that the position of the slots 1 ofwhich two areprovided in each cylinder, may be varied and that they may be displacedrelatively to one another to a certain extent.

As stated at the outset, the glow cathode may trodes consisting of acathode an'd'an an'cde,;the i discharge between which serves as asource'ofelectrons, a second anode to which an amplification currentpasses from the saidsource of electrons and a controlling electrodewhich modu-.

lates the said amplification current, said first anode being constructedand arranged as a solid shield between said cathode and said controllingelectrode, the individual parts of said cathode being constructed ashollow cathodes in the form of cylinders having longitudinal openings.

2. A system of electrodes for glow discharge amplifying tubes comprisingtwo discharge electrodes consisting of a cathode and an anode, thedischarge between which serves as a source of electrons, a second anodeto which an amplification current passes from the said source ofelecoftrons and a controlling electrode which modulates the saidamplification current, the individual parts of said cathode beingconstructed as hollow cathodes, in the form of cylinders havinglongitudinal opening-s, which terminate just .before the edges at theends of the said cylinders. .3. A system of electrodes glow dischargeamplifying tubes comprising two discharge electrodes consisting of acathode and an anode, the discharge between which serves as a .source of9 i'electrons, a second-anode to which an amplification current passesfrom the said source of electrons and a controlling electrode-whichmodulates the said amplification current, the indiand the outer walls ofsaid hollow cathodes vidual parts of said cathode being constructed ashollow cathodes, in the form of cylinders having longitudinal openingswhich terminate just before the edges at the ends of said cylinders, andmembers of insulating material covering the ends of said cylinders.

,4. A system of electrodes for glow discharge amplifying tubescomprising two discharge electrodes consisting of a cathode and ananode, the discharge between which serves as a source of ,electrons, asecond anode to which an amplification current passesfrom the saidsource of electrons and a controlling electrode which modulates the saidamplification current, the individual parts of glow cathode beingconstructed as hollow cathodes, said hollow cathodes being in'the'form'of cylinders having longitudinal openings which terminate justbefore the edges at the ends of the cylinders, and members of insulatingmaterial, covering the ends of the cylinders the surfaces of said hollowcathodes which take part in the discharge being covered with asubstancethe cathode drop of which is small.

5. A system of electrodes for glow discharge amplifying tubes comprisingtwo discharge electrodes consisting of a cathode and an anode, thedischarge between which serves as a source of electrons, a second anodeto which an amplification current passes from the said source ofelectrons and a controlling electrode which modulates the saidamplification current, the individual parts of said cathode beingconstructed as hollow cathodes, said hollow cathodes being in the formof cylinders having longitudinal openingswhich terminate just before theedges at lfi the ends of the cylinders, and members or insulatingmaterial covering the ends of the cylinders, the surfaces of said hollowcathodes which take part in-the discharge being covered with a substancethe cathode drop of which is small,

being covered with insulating substances.

. i GEORG SEIBT.

